Rotary balanced vane pump



June 4, 1949.v w, STEPHENS 2,473,309- I ROTARY BALANGED VANE PUMP Filed Nov. 2, 1945 #i W f @j @i Q @3) 70 mgm - f.. INVENTOR.

w/UAM 'r STEPHEN.

y//l BY///- ,4 TmE/VH Patented June 14, 1949 UNITED STATES PATENT OFFICEE 2,473,309 Ro'rARY BAIANCED vANE PUMP William T. Stephens, Painesville, Ohio Application November 2, 1945, Serial No. 626,213

My invention relates to uid displacement apparatus such as uid pumps and motors. The invention concerns particularly pumps of the sliding vane type.

It is an object of my invention to provide improved methods and apparatus for delivering or utilizing fluid under pressure in which high efliciency is attained and the parts of the apparatus may be machined easily.

An object of the invention is to provide a construction having a housing with a circular bore and a rotor with a shaft concentric with the bore. Another object is to provide an adjustable sealing segment in the bore between the outlet and inlet ports.

A further object is to provide easy radial sliding of the vanes.

A further object is to balance the rotor vanes hydraulically and to avoid side thrust or binding of the vanes in the slots of the .rotor in which they are carried.

Still another object of the invention is -to avoid friction causingY heat and wear at the bore and at the outer edges of the vanes.

An object is to move the blades or vanes inward by hydraulic pressure as they' pass the sealing segment in the bore.

A more specific object is to employ uid trapped 7 Claims. (Cl. 10S-136) fil ing segment. Preferably the vanes are of T-shaped cross section and T-slots are provided in the rotor for receiving the vanes. The base or T-portion of the slot is preferably radially thicker than the base or T-portion of the vane so as to provide for radial movement of the vane. Openings are provided in the rotor which lie parallel to the direction -of movement of the vanes and each vane is provided with one or more pistons each slldable in one of said openings and having a transverse notch engaging the T-portion or base of the vane. Hydraulic pressure applied to the piston by the fluid trapped between the vane and the sealing segment of the vane approaching the'sealing segment forces the vane inward radially so as to avoid friction and heating of the outer edge of the vanel and avoiding vibration or shock as the outer edge of the vane tends to contact the sealing segment. i

A better understanding of the invention will be afforded by the followingv detailed description v considered in conjunction with the accompanyas the vane approaches the sealing segment to depress the vane. Another object is to limit the radially outward movement of the vane caused by centrifugal force so as to cause the vanes to reach only a position in which the outer edges just contact the surface of the bore.

Another object ls to equalize lluid pressure under the vane in the vane carrying channel or slot of the rotor and within the bore outside the rotor. It is also an object to avoid trapping of fluid under the vane in the slot in which it is carried.

Other and further objects, features and advantages of the invention will become apparent as the description proceeds.

In carrying out the invention in accordance with a preferred form thereof.-I provide a circular-bore pump housing or shelland a concentric rotor with a concentric axis of rotation.

The pump housing is provided with inlet and outlet ports, and a sealing segment is secured in the bore between the ports to fill in the space between the rotor and the bore surface of the housing.

The rotor comprises a circular cylinder of smaller radius than the bore in the housing, the sealing segment being of a thickness corresponding with the difference between the radii of the rotor and the housing bore. A plurality of axially extending slots are cut lengthwisey in the rotor to receive vanes adapted to slide in and out radially in the rotor as they pass under the sealing` drawing in which Fig. 1 is a cross sectional view of an embodiment of my invention represented as cut by a broken plane I.-|, indicated in Fig. 2, passing through the axis of rotation of the rotor shaft; Fig. 2 is a view of a cross section of the apparatus of Fig. l represented as cut by plane perpendicular to the rotor shaft, and Fig. 3 is a fragmentary enlarged view of a portion of a vane at the approach to the sealing segment.

Like reference characters are utilized throughout the drawing to designate like parts.

For the sake of illustration I have shown and described al sliding vane pump having three radially slidable vanes but it should be understood that my invention is not limited to this f specific arrangement. In the pump illustrated in the drawing the housing comprises a cylinder or shell ,having a concentric circular bore with end cover plates i3 and I4, and preferably circular plates I5 and `li for dening the ends of a rotor chamber. Ports Il and I8 are provided at the surface of the housing bore l2 and a sealing segment i9 is secured or formed in the housing bore l2.

23 is bored to receive a shaft 21 and keyed thereto. `Suitable bearings are providedfor rotatably supporting the shaft 21 inthe pump housing. For

example ball bearings 28 and 29 may be provided. The outer ball race for the bearing 28 is secured between the cover plate i3 and the circular plate l5 and the outer ball race for the bearing 29 is secured between the circular plate I and the cover plate I4. Suitable openings are provided in the plates I5 and I5 and in the cover I4 for the shaft 21.

Preferably T-slots 3l are milled lengthwise in the rotor cylinder 23 for receiving the vanes 24, 25 and 25. The vanes 24, 25 and 25 preferably each have a T-shaped cross-section with 'a base or T-'portion 32 of less thickness or radial dimension than the base or T-portion 33 of the slot 3| in order to permit the vane to move in and out. Preferably one or more holes 34 are drilled radially in each of the vanes 24, 25 and 25 for equalizing the pressure in the base portion 33 of the vane receiving slot inside the vane with the pressure in the space between the cylinder 23 and the surface of the bore I2, and also for preventing uid from being trapped under the moving vane. In this manner any side thrust of the vanes against the edges of the slots is minimized and the vanes are allowed to move in and out freely as required.

For each of the rotor vanes one or more pistons preferably in pairs are provided, sliding in holes in the rotor cylinder `23 running parallel to the radii of the corresponding vanes. In the arrangement illustrated pistons 35 and 35 are provided slidable in openings 31 and 38 parallel to the direction of radial movement of the vane 24. Similar pistons 4I and 42 are provided slidable in cylindrical openings 43 and 44 parallel to the direction of radial movement of the vane 25, as well as pistons slidable in openings parallel to the direction of radial movement of the vane 25. In order to prevent the movement of the pistons from causing pulsations in the lines through which the fluid is being pumped, adjacent piston receiving holes of adjacent vanes are arranged to communicate with each other and with the space outside the cylinder 23. Thus the openings 39 and 43 are cut deep enough so as to communicate with each other and with an opening 45 which is cut radially in the cylinder 23 in the portion hereof between the openings 38 and 43. Similar radial openings 41 are arranged between the vanes 24 and 25 and between the vanes 25 and 26. Each of the pistons 35, 35, 4I, 42 and 45 is notched on the side to engage the side of the base or key portion 32 of one of the vanes 24, 25 or 25.

The sealing segment I9 is mounted against the surface of the bore I2 of the housing shell II between the ports I1 and I9. It is arranged to t closely against the internal surface of the shell II and to make a sliding fit with the outer surface of the cylinder 23, tight enough to seal the'joint against fluid leakage. Means such as flat headed bolt 45 are provided for securing the sealing segment I3 in position. For simplicity in the drawing only one bolt 48 is shown but it will be understood that the member is not limited to the use of only one such bolt. Preferably the sealing segment I9 is composed of spring steel and of such shape that it tends to spring inward further than the surface of the cylinder 23 so that by tightening the nut 49 on the bolt 48, the position of the inner surface of the sealing segment I9 may be properly adjusted for making a close seal with the outer surface of the cylinder 23. The outer surface of the segment I9 is flattened sumciently to provide a space 5I permitting such adjustment. A portion of the inner surface of the sealing segment I9 is cylindrical to conform substantially to the shape of the outer surface of the rotor cylinder 23. The remainder 4 of the inner surface is curved so as to form two gradual transition curves 52 and 53 providing transitions from the radius of the bore I2 of the housing shell I I to the radius of the rotor cylinder 23 and vice versa.

The pump illustrated is adapted to pump uid such as oil or the like for a fluid pressure system in either direction by reversing the direction of rotation of the rotor 22, however for the sake of simplicity it will be assumed in the explanation of the operation that the rotor 22 is rotated in the counter clockwise direction, in which case the port I1 becomes vthe inlet port and the port I8 becomes the outlet port and the iluid pumped is caused to travel in the direction of the arrows 54 through tubing 55 and 55 communicating with the inlet and outlet ports I1 and I8 respectively.

The outermost surfaces of the crosswise or T- portions 33 of the slots 3I for the vanes are in such position that the vanes are prevented from pushing against the bore I2 of the housing II with suiicient force to cause serious friction but are permitted to contact the surface of the bore I2. It should be understood that the dimensions may be such that initially the outer edges of the vanes tend to rub with excess pressure against the bore surface owing to centrifugal force but as the vanes wear in only suiiicient contact remains to seal the space between the rotor cylinder 23 and the surface of the bore I2. Consequently the space between adjacent vanes is enclosed. As the rotor rotates, uid is drawn into the port Il and swept circumferentially around the inner surface of the bore so as to be expelled through the port I9. The outersurface of the cylinder 23 is sealed at the sealing segment I9 so as to prevent fluid from beingV carried around from the outlet port I9 back 'to the inlet port I1. With the rotor in the position ilustrated the outer edge of the vane 24 has already traveled part way along the transition curve 52 of the sealing segment I9. It will be apparent that as soon as the forward edge 51 of the vane 24 has reached the forward corner 59 of the outlet port I3, some duid is trapped in the space between the vane 24 and the sealing segment I9. This space becomes continually smaller as the rotor rotates, being reduced to the volume presented at 59 in Fig. 3 when the rotor reaches the angular position illustrated. In consequence iiuid enters bore 31 in the space 5I above piston 35 and inward pressure is exerted against the outer end surface of the piston 35 causing the vane 24 to be forced inward sufficiently to relieve the friction between the corner 51 of the vane 24 and the transition curved surface 52 of the sealing segment I9. A slight flow of the trapped fluid takes place around the leading edge 51 of the vane 24, so as to provide lubrication and cooling. In this manner the vanes are depressed by hydraulic pressure so as to pass the sealing segment I9. This action avoids the shock of the vane striking this segment and also avoiding the friction, heating, and wear which would be caused if a mechanical contact between the vane 24 and the sealing segment I9 were depended upon for depressing the vane 24. With the rotor 23 rotating in the opposite direction, the same function of depressing the vane 24 would be performed by the piston 35. It will be recalled that piston 35 and 35 are arranged to engage the vanes 24 by reason of the notches therein.

The ports I8 and I1 lie between the plates I5 and I6. Suitable packing means are provided to prevent axial leakage of the uid being pumped. The circular plates I5 and I5 may be provided with conventional -ring seals G2. The shaft 21 may be packed by means of a felt packing ring 63 clamped to a ring 60 riding against a bushing 65 in the shaft opening of the cover plate It. A bent metal clamp 66 is provided for securing the felt 63 against the ring 64, and a spring 6l is providedkfor holding the ring against the bushing B5. A suitable means such as split spring rings or the like, 68 are provided for holding the inner ball races on the shaft 21.

ner edge of the felt packing ring 63 which preferably is secured to the shaft 21 by a band l.

While I have described my invention as embodied in concrete form and as operating in a specic mannerin accordance with the provisions of the patent statutes, it should be understood that I do not limit my invention thereto, since various modifications thereof will suggest themselves to those skilled in the art without'departing from the spirit of my invention, the scope of which is set forth in the annexed claims.

What I claim is:

1. A sliding vane pump comprising in combination a housing having a right circular cylin- A chamfered ring 69 is provided for holding the inl and a sealing segment between the outlet port drical bore with inlet and outlet openings and a sealing segment therebetween, a rotor having a shaft concentric with said bore, a pluralityof radially movable hydraulically balanced vanes in said rotor and hydraulic means for pressing the varies radially inward to avoid friction at the sealing segment between inlet and outlet openings of the housing.

2. A sliding vane pump comprising in combination a housing having a circular cross section bore therein, a rotor mounted in said housing having axially extending T-slots therein and vanes with T-shaped cross-section mounted in said T-slots, the outer edges of said r-slots being set in such position with respect to the dimensions of the vanes that the outer edge of the cross bar of the vanes engages the outer edge of the T-slots and the outer edges of the vanes just come in contact with the bore surface thereby avoiding excess friction between the vanes and the bore.

3. A sliding vane pump comprising in oombination a housing having a bore therein with inlet and outlet ports, a rotor mounted coaxially rotatable in said bore having radially movable vanes adapted to contact the surfaces of said bore, a sealing segment in said bore and disposed between the inlet and outlet ports of the housing and engaging the periphery of saidl rotor, said rotor having pistons therein connected to said vanes whereby a vane approaching said sealing segment produces a pressure acting upon an associated piston to depress said piston and said vane thereby avoiding friction between the vane and said sealing segment.

4. A sliding vane puinp comprising in combination a housing having a bore therein with inlet and outlet ports, a rotor rotatably mounted in said bore having radially movable vanes adapted to contact the surfaces of said bore, means for hydraulically balancing thev vanes. means for preventing said vanes from sweeping iiuid back from the outlet port to the inlet port as the vanes rotate with said rotor, and means for generating hydraulic pressure as each vane approaches the inlet port after it leaves the outlet port in order to depress the vane suillciently to minimize irictional contact oi the vane with the 6 means for preventing fluid from being swept from the outlet port to the inlet port.

5. A sliding vane pump comprising in combintion a housing with inlet and outlet ports and a movable member carrying vanes adapted to sweep duid from the inlet port to the outlet port and inlet port for preventing fluid from being returned from the outlet port to the inlet port, the sealing segment being so mounted as to trap iluid between the outlet port and the sealing segment as 'the vane approaches said sealing segment and means vresponsive to trapped pressure for depressing the vane to minimize frictional contact with said sealing segment.

(i. A sliding vane pump comprising in combination a housing having a circular-cross-section bore therein with inlet and outlet ports, a rotor of substantially circular-cross-section mounted in said bore rotatable about an axis concentric with said bore, said rotor having a smaller radius than said bore, and a sealing segment mounted in said housing having a thickness substantially equal to the diierence in radius between saidbore and said rotor whereby leakage of fluid from the outlet port to the inlet port of the bore `is arrested, wherein the sealing segment is composed of material having permanent set in a shape with an outer surface of diierent radius from the bore of said housing and an inner surface normally such as to have a radius less than the rotor surface and means whereby said segment is sprung soas to increase the internal radius to the radius of the rotor.

'7. A sliding vane pump comprising a housing having a cylindrical bore therein with inlet and outlet ports, a rotor of smaller cross-section than said bore and rotatably mounted therein, a sealing segment of spring material mounted in said bore and disposed between said ports, said sealing segment having inner and outer generally. parallel i'aces joined by tapered edge portions, said inner and outer surfaces being normally of a radius slightly greater than that of said rotor and said housing bore respectively, means to ad-k justably fasten said sealing segment in said bore and disposed substantially midway between the taperedy edges of said sealing segment, said edges of said segment normally engaging the wall of said bore with the remainder of the outer surface of said segment spaced from said bore, whereby the radius of curvature of said inner segment face may be adjusted to substantially equal that of said rotor, and a plurality of pumping vanes slidably mounted in the rotor and formed to slide across the sealing segment.

WILLIAM T. STEPHENS.

REFERENCES CITED 'I'he following referenlces are `of record in the ille of this patent:

UNITED STATES PATENTS France Nov. 22, 1910 

